The construct of risk perception occupies a key rote within most major theoretical models of health behavior. However, empirical evidence supporting the relationship between high levels of perceived risk and the practice of risk-reducing behaviors is often inconsistent. Surprisingly little is known about factors that may influence the construction of risk perceptions, how perceptions of risk may change over time, or about how smoking behavior and risk perceptions may be reciprocally related. The proposed study will address these issues by examining real-time, momentary changes in risk perceptions in the natural environment among smokers attempting cessation. Moreover, the study will examine potential differences over time in perceptions of risk among smokers who achieve successful abstinence and those who relapse. Participants will be community smokers (N=200) recruited from the greater Houston area. We expect that factors including affective state, craving, and smoking behavior will influence perceptions of smoking-relevant risk over time in the natural environment. Participants will be tracked from one week prior to their quit date through three weeks after their quit date using state-of-the-science ecological momentary assessment (EMA) procedures. All participants will receive smoking cessation treatment consisting of nicotine patch therapy, minimal contact smoking cessation counseling, and self-help materials based on the Treating Tobacco Use and Dependence Clinical Practice Guideline. Smoking-relevant health risk perceptions will be assessed using several state-of-the-science behavioral/psychological assessment technologies - EMA and "implicit" cognition psychological measures - as well as computer-administered questionnaires. Findings have the potential to shed light on important mechanisms that may influence the construction of risk perceptions and on how perceptions of risk and smoking behavior may be reciprocally related.